VIEW LIVE: Fire near State Route 76 and Interstate 15

The flames marched down a brush-covered hillside when firefighters battled a fire Thursday on Interstate 15 south, near the connector to state highway 76 in northern county.

The purple fire, as Cal Fire officials called it, has burned 175 acres near Fallbrook. Two structures were destroyed and another 12 were damaged, according to Cal Fire officials.

The fire, reported for the first time at 11:20 a.m., caused a SigAlert on I-15 heading south causing delays until all streets reopened after 1:10 p.m. The Highway Patrol from California closed the exit ramp from I-15 to Old Highway 395.

SR-76 has been closed to traffic.

Clock: drivers flee from the smoke and flames of the Lilac Fire

The fire was burning along Keys Canyon near the mobile home park Rancho Monserate Country Club.

The smoke was so thick it blocked the sun for a while, according to a NBC 7 news crew.

The division, where residents were mostly senior citizens, was evacuated, according to the Department of San Diego County Sheriff. Lt. Giantonio.

Mandatory evacuations were also in effect for:

Bonsall High School

Sullivan Middle School

Bonsall Elementary School

All West Lilac Road

Students were being moved to Fallbrook High School, district officials said.

Residents were sent to the East Valley Community Center at 2245 E. Valley Parkway in Escondido.

The risk of a forest fire in San Diego County is extreme on Thursday due to Santa Ana conditions and dry vegetation, according to the National Meteorological Service, the US Forest Service. UU And the NBC weather team 7.

Watch: Lila Fire fight aircraft in North San Diego

Humidity will be in the range of 5-15 percent, according to the US Forest Service. UU Any new fire will have a high probability of becoming large in a short period of time.

Under the warning of strong winds, valid until 4 p.m. On Friday, forecasters expect the strongest winds after dawn in the morning until Thursday afternoon.

A fire weather warning is valid until 8 p.m. Saturday means that any fire that develops will spread quickly and will be very difficult to control.

Whitney Southwick of NBC 7 said that humidity was at 7 percent with the temperature of the mid-70s.

Wind gusts in the fire area were recorded from a northeast direction as strong as 51 mph in Highway 76 in Pala, according to the National Meteorological Service. Winds along I-15 near the fire were recorded between 30 and 35 mph.

No other information available.

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